Upland rice (Oryza sativa L.) varieties response to weed management practices and plant stand densities in a moist savanna of Nigeria

Abstract

Planting of weed- competitive rice cultivar at optimum seedling per hill is an efficient weed management practice that can contribute to weed suppression and increased grain yield. A study was conducted on a farmer’s field at Badeggi, Nigeria to determine the response of upland rice varieties to weed management practices and plant stand densities. Lower weed dry matter was observed in NERICA 7 compared to NERICA 1, 2 and 4. While NERICA 4 produced more tillers, NERICA 1, 4 and 7 produced longer panicles and NERICA 7 more grains per panicle. Higher grain yield was associated with NERICA 1 and 4 varieties. Hoeing at 3 and 6 weeks after sowing (WAS) and application of pre-emergence (PE) butachlor followed by (fb) hoeing at 6 WAS reduced weed dry matter production compared to the weedy check. Production of longer panicles, more grains and higher grain yield were associated with PE butachlor fb post-emergence (POE) Orizoplus, PE butachlor fb hoeing at 6 WAS, and hoeing at 3 and 6 WAS. Weed dry matter produced was generally low with six plant stands per hill treatment. Two and four plant stands per hill produced panicles with more grains, while four and six plant stands per hill produced plants with more panicles and grains per unit area. This result suggests that NERICA 7 combined with hoeing at 3 and 6 WAS orapplication of PE butachlor fb hoeing at 6 WAS, and 6 plant stands per hill can effectively control weeds. The use of NERICA 1, NERICA 4 in combination with PE butachlor fb POE Orizoplus, or hoeing at 3 and 6 WAS and 4 or 6 plant stands per hill resulted in increased grain yield of upland rice.